Electrostatic precipitating plate



Oct. 13, 1942. H; w. POUND ETAL ELECTROSTATIC FRECIPITATING PLATE 2 Sheets-Sheet 2 Hon/Ano Mipaf/Nn MfnzfI/SH l INVE/Vos @o/QNfw Original Filed April 13, 1939- Patented Oct. 13, 1942 ELECTRDSTATIC PRECIPITATING PLATE Howard W. Pound and Merle K. Rush, Louisville, Ky., assignors to American Air Filter Company,

Ine., Louisville,

ware

Ky., a corporationv of Dela- Orlginal application April 13, 1939, Serial No. 267,562. Divided and this application January 12, 1940, Serial No. 313,586

comme Our copending application, Serial No. 267,562, filed April 13, 1939, which issued Aug. 27, 1940 I3-i3 of Figure l2.

as Patent #2,212,885, describes and claims a.

Self-cleaning electric gas cleaner, wherein a series of electrical precipitating plates vare mounted on a conveyor for movement successively through an oil bath, in which they are cleaned and coated with oil, and a pass area, in which they are elec-A trically charged to precipitate gas borne particles having electrical charges previously imparted to them in an ionizing chamber. This application which, is a division of our aforesaid application, is directed to the structure and arrangement of said plates.

The principal object of the invention is to provide a novel electrostatic 'precipitating plate arrangement in which objectionable electricaly Figure 13l is a fragmentary section along line The filter illustrated comprises: a housing, preferably composed of sheet metal; an upright conveyor, having upstream and downstream sections adjacent upstream and downstream areas,

- mounted within the housing; and a filter medium discharges between adjacent plates are miniv groups f such plates in a novel form of cell 'which can be easily, quickly and inexpensively mounted on the conveyor. The housing or casing i is of conventional form having a front inlet opening 2 adjacent the upstream pass area, a rear outlet opening 3 adjacent the downstream pass area, a bottom oil bath 4, and, between pass areas above the bath, a centrally arranged ionizing chamber defined by the vertical side walls of the housing in cooperation with horizontally arranged top and bottom metal partitions l and 6. An'angle iron conveyor guide 'l is vertically arranged along opposite margins of each pass area. l each conveyor guide being rigidly secured to the adjacent vertical sidewall of the housing. upper and lower -ends of eachguide may be curved slightly to conform to the conveyor path.

manufactured and readily secured in assembled relation to form a movable illter medium.

The invention is lillustrated in the accompanying drawings as applied to the self-cleaning electrical gas cleaner disclosed in our aforesaid copending application. In said drawings:

Figure 4 is a, section through 'une '4 4 er' Figure 3:

Figure 5 is a schematic view showing the relation between twoadjacent plates;

Figure 6 is a perspective of 'a filter cell; Figure 7 is a perspective in the insulator molding for two diagonally opposite corners of the cell: v

Figure 8 is a similar -view of the molding for' the other two corners of the cell;

Figure 9 is an end elevation of one part of the cell with the end plate removed;

Figure 10 is a section through line l-ll oi Figure 9; v

Figure 11 is a section corresponding to Figure 10 but with the molding members removed.

AFigure -12 is a fragmentary section taken lis Figures 2-4 inclusive. As illustrated, each alterthrough line I 2-I2 of Figure l: and

The upright conveyor includes suitable shafts, sprockets, and sprocket chains. The shafts comprise a pa'ir of horizontally spaced transversely arranged upper shafts 8 and 9 positioned above the top partition 5 and a similarly arranged pair of lower shafts i0 and Ii positioned below the bottom partition 8. The upper shafts 9 Vand 9 and the lower shaft Ill are all rotatably mounted on suitable bearings (not shown) which are rigidly secured to the housingi. The other lower shaftv l I is aiioating shaft. It is resiliently urged downwardly by one or more springs I2 suitably mounted between the shaft I I and the bottom partition 8. The proper spacing between lower shafts l0 and Il is maintained bya radius rod i3 which extends from one shaft to the other and is plvotally mounted on both. Each shaft carries. a pair of laterally spaced sprockets, one adjacent each side of the housing. The sprockets of each pairare designated by the corresponding shaft numeral followed by the letter a; viz 8a,- Qa, Na and II a. `The sprockets conventionally .cooperate to carry a pair of sprocket chains .|4,

each sprocket being suitably notched to engage the corresponding chain.

The conveyor chains I4 extend along opposite sides of the housing and over the outer faces of the adjacent conveyor guides 1; Eachchain is composed of an endless succession of alternate links and another series f intermediate links plvotally secured to each other. The structure and arrangement of each link is illustrated in.

The"

nate link includes a pafir of laterally spaced straps l5, and each intermediate link, a'similar pair of straps I 6. The outer edge of one strap in each link is extended or ilanged outwardly thence laterally over the chain proper to form a securing lug Ila von alternate links and a lug lia on intermediate links. The lugs lia may be tapped or otherwise provided with a threaded opening to receive the securing means for the filter medium. -The intermediate or connecting links are made wider than alternate links and are telescopically iltted over and pivotally secured thereto.

The illter medium is composed of a succession of electrically separate, narrowly spaced plates Il which cooperate to denne along and across the medium a plurality of narrow gas passages extending through the medium. In this succession of plates. the alternateplates form one series and the intermediate plates another. While straight flat plates could be used, the use of bent plates is preferred in order to secure a gas passage between plates of desired gas-dow depth and diagonally opposite corn-ers of the cell, are of the character shown in Figure "I, while the other two moldings, which are designated lab and intended for application to the other two diagonally opposite comers, are of the character shown in Figure 8.

Each of the moldings lia is integrally provided with two spacer blocks I9, along its right edge, one for each pairof alternate plates, and with two spacer blocks 2l, along its left edge, one for each pair of intermediate plates, the left blocks 20 being offset both laterally and longitudinally from the right blocks I9. Each block projects into, and traverses the space between, the corresponding pair of plates. Each pair of plates is mechanically secured to the interposed spacer blocks, and preferably electrically connected to tween adjacent plates, the tendency of such discharges to occur being more pronounced at the edges of the plate than along their intermediate surfaces.

Vlliccordingly (see Figure 5), each plate I1 is provided with a modified zigzag shape so as to present spaced flat air ilow edge sections lla and Hc and one or more flat intermediate precipi tatipg sections llb, only one being shown, extending at an angle to the edge sections. The size of the smaller angle formed between edge and intermediate sections will, of course, depend upon the spacing desired, between intermediate sections, for a given spacing between air flow edge sections. In any event, such angle will be larger than 100 and smaller than 150, an angle of 120 being shown.

In further accordance with our invention, the possibility of objectionable electrical discharges occurring between plates is additionally minimized by making the alternate plates longer than the intermediate plates so as to increase the spacing between their endedges.

The plates may be separately mounted on the conveyor chains but preferably are rigidly mounted in groups, of say eight plates, to form illter cells, the cells ,as a whole being mounted on the chains. The structure of each cell is illustrated in Figures 6-11 inclusive.

each other, by means of a bolt passing from one plate to the other through the intervening block. Each spacer blockA I9 for the alternate vplates extends into the space between the adjacent shorter intermediate plates and the end of the cell as a whole. However, to accommodate the spacer blocks 20 of the intermediate plates, the interposed alternate plates are suitably notched.

The structure and arrangement oi the moldings Ib are identical to that of the moldings Ila except that the spacer blocks l! are placed at the left edge of the molding andthe blocks 20A at the right edge thereof.

While the cells may be mounted on the conveyor in any suitable way, each cell, preferably, is mounted upon the corresponding links of the conveyor by providing each of its ends with an end plate 22 having a securing flange 22a which is secured to the securing lug I5a on the corresponding link. Each end plate 22 preferably is mechanically secured to the longer alternate plates of the cell, by welds or otherwise, and, to

, other and to the conveyor chain, which may be and, preferably, is grounded. While the individual plates of each intermediate pair may be electrically connected to each other through the spacer-block bolts, all of them, preferably, are electrically connected together, as a unit, by crossover straps 23 which project centrally from the intermediate plates, through that air-flow face of the cell which lies adjacent the conveyor, the straps forming a common collector bar. With this arrangement, the precipltator plates may be electrically charged by impressing suitable voltage, say 5,000 to 6,000 volts, between ground and the collector bars of each cell.

In the arrangement shown, a precipitating Avoltage need be maintained only across such h vertically mounted on the casing to extend centrally in front of the downstream pass. The bus bar 2| is secured at its upper and lower ends to insulators 25 which are mounted on the top and bottom partitions 5 and 6 of the ionizing chamber. The bar carries a series of spring metal brushes 2Ia positioned to have sliding contact with the collector bars 23 of the cell.

In operation, the conveyor, and the gas being cleaned, move in the directions indicated in the drawings. The gas is mechanically cleaned as it passes between plates in the upstream pass. Between passes, smoke and Vother particles remaining in the gas, are electrically charged by some suitable ionizer, not shown. In the downstream pass, the charged particles are electrically precipitated on the plates as a result of the precipitating voltage applied to such plates. In this connection, it may be noted that, at the bottom of the conveyor, the cells hang downwardly into the oil in more r less separated relation. As they emerge from the bath, they swing back into proper filtering relation, andI in this relation, pass upwardly into and through the downstream pass. As they vapproach such pass, they are electrically connected to the precipitating voltage supply line through the engagement of the busbar brushes 24a with the collector bars 23 of the cells. The brushes are so spaced that contact is maintained with the collector bars 23 at all times during their travel through the air-cleaning section of the downstream pass. Consequently, the plates in such section are electrically conditioned, at all times, to precipitate charged particles borne in the air passing between them. Any particles once precipitated in the downstream pass will be rmly bound to the precipitator plates by the fresh coating of oil which' the plates received during their passage through the bath and, therefore, ultimately carried into the bath and there removed in the usual way.

Having described our invention, we claim:

1. An electrical gas cleaning precipitating cell, I

comprising: a group of narrowly spaced plates presenting end face edges and front andrear air-ow face edges; an insulator molding arranged, adjacent each end of each air-flow face, to traverse the edges of successive plates, said molding having spacer blocks, extending into the space between and bearing on spaced plates to space and insulate them; and means for holding said moldings in position 2. An electrical gas cleaning precipitating cell, comprising: a group of narrowly spaced plates presenting end face edges and front and rear air-flow face edges; and means for securing the plates together as a unit, said means including end plates secured to the ends of alternate plates; and insulator moldings connecting the intermediate plates to alternate plates to space and insulate them.

3. A self-cleaning electrical gas cleaner comprising: a succession of electrical precipitating cells, each cell being composed of a series of alternate plates, a series of intermediate plates, and insulator means connecting the alternate plates to and spacing them from the intermediate plates; a felt-like conveyor movable through' cellcleaning and gas-cleaning areas; means for I l 3 mounting said cells on said conveyor; and means for moving the conveyor.

4. An improvement in electrical gas-cleanin precipitating cells of the character having a series of plates assembled and supported in narrowly spaced relation with their front and rear edges and their opposite end edges respectively forming front and rear gas-flow faces and opposite end faces, said plates dening narrow gas-flow passages extending from one gas-now face to the other wherein: each'plate is bent to provide substantially parallel front and rear edge sections and an intermediate precipitating section extending at such angle to the edge sections as to produce a spacing between the corresponding front and rear edges of adjacent plates substantially greater than the spacing between the precipitating surfaces thereof, while the alternate plates are made suilciently longer from end to end than the intermediate plates as to produce a similar relation in the spacing between the corresponding end edges of adjacent plates and the precipitating surfaces thereof.

5. The improvement dened in claim 4 wherein: the end faces are covered by end plates secured to the alternate plates.

6. An electrical gas-cleaning precipitating cell comprising: a series of plates assembled in narrowly'spaced relation with their front and rear edges and their opposite end edges respectively forming front and rear air-flow faces and opposite end faces, said plates defining narrow gasflow passages extending from one .gas-now face to the other; insulator moldings traversing the edges of successive plates, said moldings having spacer blocks projecting into the space between and bearing upon spaced plates to space and insulate them; and means for holding said moldings in' position.

comprising: a series of plates assembled in narrowly spaced relation with their front and rear edges and their opposite end edges respectively forming 'front and rear air-flow faces and opposite end faces, said plates dening narrow gasow passages extending from one gas-ow face to the other; an insulator molding arranged, adjacent each end margin of each air-flow face, to traverse the edges of successive plates, said molding having alternate-plate and intermediate-plate spacer blocks respectively extending into the space between and bearing on pairs of spaced alternate plates and intermediate plates to space and insulate them; and means for rigidly securing to each spacer block the plates separated by it.

' HOWARD W. POUND.

MERLE K. RUSH.

CERTIFICATE or CORRECTION.. Patent No. 2,298,510. october 15, 19kg.

\`HowARD w. ROUND, RT AL.,

It is hereby certified tl'xat error appears in the printed specification of the above numbered patent requiring correction as follows: Page 5, first column, line 57, claim 5, for "felt-like" read belt1ike; and that the said Letters Patent should be read with this correction-therein that the same may conform to the record f the case in'the Patent O ffice.

signed and sealed this 5th day of January, A. D. 1915.

enry Van Arsdale, (Sea-l) Acting Commissioner of Patents. 

